Eye tracking is the process of measuring either the point of gaze (i.e. where one is looking) or the motion of an eye relative to the head. Typically, an eye tracker is a device used for measuring eye movements and/or positions. There are a number of methods for measuring eye movement. Currently, the most widely used are video-based eye trackers, by which a camera focuses on one or both eyes and records their movement as the viewer looks at some kind of stimulus. Most modern eye-trackers use the center of the pupil and infra red non-collimated light to create corneal reflections. The vector between the pupil center and the corneal reflections may be used to compute the point of regard on surface or the gaze direction.
Eye tracking setups vary greatly; some are head-mounted, some require the head to be stable (for example, with a chin rest), and some function remotely and automatically track the head during motion.
The eye tracking technology is used in various fields. For example for detecting a gaze of a driver of a vehicle in order to assist the driver's driving (e.g. for determining whether or not the driver is driving inattentively).
Another known technique is detecting movement of a pupil of a wearer of a head-mounted device, and determining, based on the detected movement, inputs to a user interface. For example, by using eye gaze detection, the head-mounted device may change a tracking rate of a displayed virtual image based on where the user is looking. Gazing at the center of the field of view may allow for fine movements of the virtual display (e.g. slow scrolling). Gazing near an edge of the field of view, may provide coarser movements (e.g. fast scrolling).
A somewhat similar technology to tracking head movements of a user is a technology which is sensitive enough so that only small head movements are required for the detection, while the user's eyes do not leave the screen.
The mouse is a common peripheral input device of any typical computer system. It can track the user's control motion (usually detected by a trackball or optical detection unit) and the cursor on the screen of the display will be shifted in a way that corresponds to the user's control motion. Besides, the user may select any item on the display or execute commands during word processing or web browsing by clicking the buttons of the mouse device. Typically, when the user presses a button of a mouse device, the button shifts down and triggers an electrical switch on a circuit board inside the mouse device, so the electrical switch is turned on and sends an electrical signal to a connected computer system (either by wire or wirelessly). Then the computer system generates an event associated with the click on the screen of the display corresponding to the electrical signal. After the user releases the button, an open circuit is formed due to disappearance of the pressure. Meanwhile, the button generates a feedback force in response to the foregoing pressure and reverts to its original rest state.
Because the user presses the buttons of the mouse device frequently, the buttons hit the electrical switches very often. The hardness of the button is not high enough so that the button may be sunken or, distorted after hitting the electrical switch for a large number of times. In such a case, the button will not be sensitive as expected, and will have an adverse effect on the user's operation since he/she would have to press the button harder in order to get a successful connection with the electrical switch.
In addition, there are times where a number of operations need to be carried out in a computer system, and having a single cursor implies that they need to be carried out serially, a fact that leads to a too long period of time for the execution of these operations, a period that should preferably be shortened.